Improve reliability of non-MRI CI

Jobs still occasionally freeze/time-out in test step.

1. Allows jruby-head to fail (as done previously)

2. Actions - change all Ubuntu JRuby OS's to 20.04 (18.04 uses JDK-8, 20.04 uses JDK-11)

3. Integration tests (cluster, pumactl, single) - only run parallel on MRI Rubies

4. `helper.rb` - `TestSkips` - add `JRUBY_HEAD` constant for use with non-parallel conditionals and skips

5. `test_puma_server.rb` - jruby-head - run non-parallel

6. `test_puma_server_ssl.rb` - `TestPumaServerSSLClient` tests - non-parallel on JRuby, add `Errno::ECONNRESET` to client net/https rescue for TruffleRuby

7. `test_puma_server_ssl.rb` - `TestPumaServerSSL#test_http_rejection` - add `Net::ReadTimeout` to client net/https rescue for TruffleRuby

Update test_puma_server_ssl.rb

.github/workflows/non_mri.yml

@@ -18,16 +18,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ ubuntu-20.04, ubuntu-18.04, macos-10.15 ]
+        os: [ ubuntu-20.04, macos-10.15 ]
         ruby: [ jruby, jruby-head, truffleruby-head ]
         no-ssl: ['']
         include:
-          #- { os: ubuntu-18.04 , ruby: jruby-head, allow-failure: true }
+          - { os: ubuntu-20.04 , ruby: jruby-head, allow-failure: true }
           - { os: ubuntu-20.04 , ruby: jruby, no-ssl: ' no SSL' }
         exclude:
-          - { os: ubuntu-20.04 , ruby: jruby }
-          - { os: ubuntu-20.04 , ruby: jruby-head }
-          - { os: ubuntu-20.04 , ruby: truffleruby-head }
           - { os: macos-10.15  , ruby: jruby-head }
 
     steps:
@@ -59,7 +56,7 @@ jobs:
 
       - name: test
         id: test
-        timeout-minutes: 20
+        timeout-minutes: 15
         continue-on-error: ${{ matrix.allow-failure || false }}
         if: success() # only run if previous steps have succeeded
         run: bundle exec rake test:all

test/helper.rb

@@ -108,6 +108,8 @@ module TestSkips
 
   SIGNAL_LIST = Signal.list.keys.map(&:to_sym) - (Puma.windows? ? [:INT, :TERM] : [])
 
+  JRUBY_HEAD = Puma::IS_JRUBY && RUBY_DESCRIPTION =~ /SNAPSHOT/
+
   # usage: skip_unless_signal_exist? :USR2
   def skip_unless_signal_exist?(sig, bt: caller)
     signal = sig.to_s.sub(/\ASIG/, '').to_sym

test/test_integration_cluster.rb

@@ -2,7 +2,7 @@ require_relative "helper"
 require_relative "helpers/integration"
 
 class TestIntegrationCluster < TestIntegration
-  parallelize_me!
+  parallelize_me! if ::Puma.mri?
 
   def workers ; 2 ; end
 

test/test_integration_pumactl.rb

@@ -3,7 +3,7 @@ require_relative "helpers/integration"
 
 class TestIntegrationPumactl < TestIntegration
   include TmpPath
-  parallelize_me!
+  parallelize_me! if ::Puma.mri?
 
   def workers ; 2 ; end
 

test/test_integration_single.rb

@@ -2,7 +2,7 @@ require_relative "helper"
 require_relative "helpers/integration"
 
 class TestIntegrationSingle < TestIntegration
-  parallelize_me!
+  parallelize_me! if ::Puma.mri?
 
   def workers ; 0 ; end
 

test/test_puma_server.rb

@@ -3,7 +3,7 @@ require "puma/events"
 require "net/http"
 
 class TestPumaServer < Minitest::Test
-  parallelize_me!
+  parallelize_me! unless JRUBY_HEAD
 
   def setup
     @host = "127.0.0.1"

test/test_puma_server_ssl.rb

@@ -216,7 +216,8 @@ class TestPumaServerSSL < Minitest::Test
 
     tcp = Thread.new do
       req_http = Net::HTTP::Get.new "/", {}
-      assert_raises(Errno::ECONNREFUSED, EOFError) do
+      # Net::ReadTimeout - TruffleRuby
+      assert_raises(Errno::ECONNREFUSED, EOFError, Net::ReadTimeout) do
         http.start.request(req_http) { |rep| body_http = rep.body }
       end
     end
@@ -245,7 +246,7 @@ end if ::Puma::HAS_SSL
 
 # client-side TLS authentication tests
 class TestPumaServerSSLClient < Minitest::Test
-  parallelize_me!
+  parallelize_me! unless ::Puma.jruby?
 
   CERT_PATH = File.expand_path "../examples/puma/client-certs", __dir__
 
@@ -286,7 +287,8 @@ class TestPumaServerSSLClient < Minitest::Test
         req = Net::HTTP::Get.new "/", {}
         http.request(req)
       end
-    rescue OpenSSL::SSL::SSLError, EOFError
+    rescue OpenSSL::SSL::SSLError, EOFError, Errno::ECONNRESET
+      # Errno::ECONNRESET TruffleRuby
       client_error = true
       # closes socket if open, may not close on error
       http.send :do_finish
@@ -302,7 +304,7 @@ class TestPumaServerSSLClient < Minitest::Test
       assert_equal subject, events.cert.subject.to_s if subject
     end
   ensure
-    server.stop(true)
+    server.stop(true) if server
   end
 
   def test_verify_fail_if_no_client_cert